This invention relates to a transmission shift lever assembly for a vehicle transmission control system.
In an electro-hydraulically controlled power shift transmission or in a hydro-mechanically controlled transmission, the shift lever can be moved with low effort between gears or from neutral into a forward or reverse gear. If the operator leaves the shift lever in neutral while the engine is running, then an inadvertent movement of the shift lever could cause an accidental shift of the transmission into gear. A mechanism which would deter such accidental shifting is desired. A known power shift transmission includes a finger actuated collar to release the shift lever from neutral. Automobiles have used thumb-actuated buttons on shift levers to prevent the shift lever from being accidentally moved from park into reverse, for example. Such collars or buttons may be difficult to release if the operator is wearing gloves.
A transmission shifter neutral lock is shown in U.S. Pat. No. 4,282,769, issued 11 Aug. 1981 to Sandrock. However, in this system a locking arm must be manually rotated into and out of a locking position by means of a T-shaped handle. Another transmission shifter neutral lock is shown in U.S. Pat. No. 4,163,398, issued 7 Aug. 1979 to Johnston. However, in this system a pair of locking levers must be manually rotated into and out of a locking position by means of an actuating lever. It would be desirable to have a neutral locking mechanism which locks automatically and which can be easily unlocked by manipulation of the shift control lever.
Another transmission shifter neutral lock is shown in U.S. Pat. No. 4,671,378, issued 9 Jun. 1987 to Korrect et al. However, this mechanism requires a bulky mechanism including a shaft and a bracket having a slot with a "cut-out" which receives the transmission control lever. It would be desirable to have a neutral locking mechanism which is simple and compact.